Coal-cutters having cutter chains driven in tension



W. GILLESPIE Aug. 4, 1959 COAL-CUTTERS HAVING CUTTER CHAINS DRIVEN IN TENSION Filed Jan. 28, 1957 37/ QW V W WV By Q I Attorney:

COAL-CUTTERS HAVING CUTTER CHAIN DRIVEN IN TENSION Application January 28, 1957, Serial No. 636,743

Claims priority, application Great Britain February 1, 1956 5 Claims. (Cl. 262-30) This invention relates to mining machines known as coal-cutters for cutting into the face of a seam of coal or other mineral, such coal-cutters being of the type in which each when in use is equipped with superposed cutter-chains that work in endless paths around a jib structure extending from a body which encases chain-driving mechanism. In the operationof such a machine, the chains travel inwards-that is, from the end of the jib structure towards the body-and present a working front of cutting tools. These tools, usually called picks, are fitted in an endless series of pick-boxes, all interconnected and forming the links of the chains.

Mining machines such as described may have to be constructed to work under conditions in which at least one auxiliary jib, above or below a main jib, must be limited in length so as to extend entirely beyond the limits of the machine body. An instance of such a machine is described in United States Patent 2,737,379 of David Jackson, which machine when used for longwall mining is adapted to ride upon a mine-face conveyor. Thus, the machine has an under-slung auxiliary jib of which the length is such that it is laterally clear of the conveyor underneath the machine body. I

The object of the present invention is to provide a coal-cutter adapted to work under conditions such as described in which the cutter-chains are driven in such a manner that they are in tension when travelling across the working front of the jib structure.

Therefore, the invention is a coal-cutter of the type stated in which the jib structure comprises a main jib extending from the machine body and an auxiliary jib, the jibs being arranged one above the other at upper and lower working levels, and in which the chain-driving mechanism includes a power-driven chain-driving sprocket wheel at about the inner end of the main jib, a chaindriving sprocket-wheel at about the inner end or the auxiliary jib, chain-guiding means at the outer ends of both jibs, and drive-gearing connected with the chaindriving sprocket-wheel of the auxiliary jib so that both chain-driving sprocket-wheels rotate in the same direction. Thus, the jib structure, when equipped with cutter chains, presents at its workingv front two superposed lengths of chains which are both pulled inwards by the chain-driving sprocket-wheels and which-therefore are both driven in tension.

An example of a'coal-cutter incorporating the invention is shown in the accompanying drawings, in which:

Figs. 1A and 1B together form a sectional elevation of the jib structure and associated-parts of the coal-cutter o y- I Fig. 2 is a section on the plane 22 of Fig. 1A.

In the example, the jib structure consists of a main upper jib and an under-slung auxiliary jib 11 arranged to work just above floor level. The upper jib is bolted at its inner end at 12, to a swivel-head 13 mounted in the machine body 14. There is journalled in this body a chain-driving sprocket-wheel 15, which is co-axial with the swivel head and is driven from an electric motor through a train of speed-reduction gears, all in the customary manner, the terminal gear-wheel 16 of the train being shown. The base of the body 14 includes side anglesection bars 17 which are provided with hearing plates 18, the parts 17 and 18 being adapted as shown to slide upon the side frames 19 of a scraper conveyor.

At the outer end of the jib structure there is journalled on a fixed axle 20, so as to be freely rotatable, a sprocketwheel 21 which is at the same level as the chain-driving sprocket-wheel 15 and is aligned with the usual chainguiding side-and-end channel 22 of the upper jib. Accordingly, these sprocket-wheels 15, 21 and channel 22 form the requisite support for the upper cutter-chain, which is represented in dot-dash outline at 23, the outer sprocket-wheel 21 being driven by this chain 23. The hub 24 of this chain-driven sprocket-wheel has keyed to it, at 25, a gearwheel 26, which is at an intermediate level in relation to the two jibs 10 and 11.

. At the inner end of the lowerjib 11, there is journalled on a fixed axle 30 in the jib structure another sprocketwheel 31. This wheel has a hub 32 to which there is keyed at 33 another gearwheel 34, which is of the same level as the lower-jib sprocket-wheel 31, both this sprocketwheel and the chain-guide being aligned with the usual chain-guiding side-and-end channel 36 of the lower jib..

Thus, the chain-guide 35, sprocket-wheel 31 and channel 36 form the requisite support for the lower cutter-chain 37, which is represented in dot-dash outline.

There is also .journalled in the jib structure, between the two gearwheels26, 34, an idler gearwheel 40 which meshes with both, forming with them a train of which the outer members 26, 34.both turn in the same direction and ,at the samespeed, each in unison with the sprocket! wheel 21 or 31 to which. it is connected. Accordingly, both cutter-chains 23, 37 will travel at the same speed and inthe same direction. Moreover, the upper and lower chain stretches at the working front of the jib structure .will travel inwards, as indicated by the arrows 41 and 42 in Fig. 1, each front stretch being pulled by the sprocket-wheel 15 or 31 at its inner end.

In the example, the upper and lower chains 23, 37 Work near one another to ensure that there can be no intervening uncut slab of. coal or other mineral.

I In the example, the chain-guide 35 at the outer end of the lower jib 11 is a frame with a semi-circular outer end 43 and parallel sides 44, this frame being fitted to, the jib structure and being adjustable lengthwise of thejib, by an appropriate screw device, to regulate the tension ofrthe lower'chain 37. The work of regulation does not affect the length of the upper jib 10 or the tension of the upper cutter-chain 23. In the example, the screw device comprises a nut 50, which is rotatable about its axis but is held against axial displacement by upper and lower projections 51, 52 on the lower-jib structure, and a-screw 53 which is threaded through the nut and is axially displaceable but -is held against rotation by an end plate 54. This end plate is a loose sliding fit. within the jib structure,,as Fig. 1 shows. The nut 50 is ro-' tatable by means of a Nertical turnable shaft 55, shown in Fig.2, .witha'squared head 56which projectsthrough 50. The arrangement is such that a worker can turn the shaft 55 and by so doing will either cause the frame 35 to be pushed outwards by the screw 53 in order to increase the lower-chain tension or cause the screw 53 to be withdrawn in order to reduce the lower-chain tension.

Correspondingly, the main upper jib is extensible in length for regulation ofthe tensionoftheupper cutter-chain 23. In the example, regulation of this chain also is effected by a screw device. This device comprises a nut 70, which is rotatable about its axisbut isheld against axial displacement by upper and lower projections 71, 72 on the upper-jib structure, and a screw 73 which is threaded through the nut and is axially displaceable but is held against rotation by an end plate '7 4. The nut 70 is rotatable by a worker by means or a turnable vertical-axis stub 75 with a projecting squared head 76. This stub has a bevel gear-wheel 77, Fig. 2, meshing. with another bevel gear-wheel 78 provided on the nut.70. The mode of operation is as described with reference to the tension-regulating parts 50 to 62.

In operation of the coal-cutter, it is advanced by appropriate haulage gear along the conveyor framework 19; the main-jib cutter chain 23 cuts from the coal seam 80 a kerf 81 at a level. above the mine floor 82, and the auxiliary-jib cutter chain 37 cuts away the layer 83 which otherwise would be left below the kerf 81.

In the example, each of the cutter chains 23 and 37 is driven by a sprocket-wheel 21 or 31 which pulls its working stretch of chain inwards. Thus, the arrangement has to be distinguished from any previously known coalcutter having two or more superposed cutter-chains including a chain (or chains) the working stretch of which is driven under compression by a sprocket-wheel at the outer end of the jib. There are serious disadvantages of a compressive drive; notably, the links of the chain, consisting of the usual pick-boxes, tend to bunch and twist and thus to bear irregularly upon the chain-guiding channel of the jib and upon. the sprocket teeth.-

Any of various modifications within the scope of the wheels, a cutter-chain-driving sprocket wheel at the inner end of the auxiliary jib, a cutter-chain guide at the outer end of the auxiliary jib, an auxiliary cutter-chain trained round the auxiliary jib and the last-mentioned sprocketwheel and guide, and drive-gearing which is connected between the cutter-chain-driven sprocket-wheel of the main jib and the cutter-chain-driving sprocket-wheel of the auxiliary jib and which rotates the latter sprocketwheel in the same direction as said power-driven sprocketwheel so that the cutting stretches of both cutter-chains are driven in tension.

2. A coal cutter according to claim 1 in which the drive-gearing comprises a train of inter-meshing gearwheels, the terminal gearwheels of this train being re spectively secured to the cutter-chain-driven sprocketwheel of the main jiband to' the cutter-chain-driving sprocket-wheel of the auxiliary jib.

3.- A coal-cutter according to claim 1 in which the auxiliary jib has means for adjusting its cutter-chain guide relative to its cutter-chain-driving sprocket-wheel in order to adjust the tension of the auxiliary cutter-chain without changing the distance between the cutter-chain-driveu and cutter-chain-driving sprocket-wheels of the main and auxiliary jibs, respectively.

4. A coal-cutter comprising a body having a base adapted to bear upon the framework of a coal conveyor for travel of the coal-cutter along the conveyor, a swivelhead mounted in the body, a power-driven rotatable sprocket-wheel journalled in the body co-axially with the swivel-head, a main jib for a cutter chain, said jib extending above conveyor level laterally from its inner end on the swivel head, an auxiliary jib underneath the main 1 jib forming part of the same structural unit as the main claims, which follow, may be made.- For instance, in '7 the example, the auxiliary jib 11 is under-slung. Instead, it might be superposed upon the main jib.- Moreover, the coal-cutter may have more than two jibs in superposed relation. For instance, a single main jib might be associated with twoauxiliary jibs, say one above the main jib and one below it; and in this event the outer chain driven sprocket-wheel of the main jib has an axle to which are secured two gearwheels, one above and one below and each driving a train of gearwheels which drives a chain-driving sprocket-wheel at the inner end of the associated auxiliary jib. Alternatively, there might be two auxiliary jibs both above a single main jib, or both below it. Alternatively, a coal-cutter may have two main jibs each carrying an auxiliary jib.

I claim:

1. A coaLcutter comprising a body, a swivel-head mounted in the body, a power-driven rotatable sprocketwheel journalled in the body co-axially with the swivelhead, a main jib for a cutter chain, said jib extending laterally from its inner end on the swivel head, an auxiliary jib carried by the main jib, the jibs being arranged one above the other and the auxiliary jib extending from its inner end at a place laterally clear of the body to practically the full stretch of the main jib, so thatthe auxiliary jib is substantially shorter than the main jib which carries it and the outer ends of both jibs are directly above and below one another, a cutter-chain-driven sprocket-wheel at the outer end of the main jib, a main cutter-chain trained round the main jib and both of said sprocket jib the auxiliary jib extending directly above floor level from its inner end at a place laterally clear of the body and conveyor to practically the ,full stretch of the main jib, so that the auxiliary jib is substantially shorter than the main jib and the outer ends of both jibs are directly above and below one another, a cutter-chain-driven sprocket-wheel at the outer end of the main jib, a main cutter-chain trained round the main jib and both of said sprocket-wheels to cut above conveyor level, a cutterchain-driving sprocket-wheel at the inner end of'the auxiliary jib, a cutter-chain guide at the outer end of the auxiliary jib, an auxiliary cutter-chain trained round the auxiliary jib and the last-mentioned sprocket-wheel and guide to cut away the coal left below the level of the main cutter-chain, and drive-gearing which is operatively connected with said power-driven rotatable sprocket-wheel and which rotates said cutter-chain-driving sprocketwheel in the same direction as said power-driven sprocketwheel so that the cutting stretches of both cutter-chains are driven in tension. a

5 A coal-cutter according to claim 4 in which the drivegearing. that drives the cutter-chain-driving sprocket-wheel of the auxiliary jib is connected between this sprocketwheel and the cutter-chain-driven sprocket-wheel of the main jib.

References Cited in-the file of this patent UNITED STATES PATENTS Germany Feb, 23, 1953 

